Question

1. apply concepts write and balance equations for the following reactions: a. iron metal and chlorine gas react to form solid iron(iii) chloride. b. solid aluminum carbonate decomposes to form solid aluminum oxide and carbon dioxide gas. c. solid magnesium reacts with aqueous silver nitrate to form solid silver and aqueous magnesium nitrate.

Explanation:

Part a

Step1: Write the unbalanced equation

Iron (Fe) reacts with chlorine gas ($\ce{Cl2}$) to form iron(III) chloride ($\ce{FeCl3}$). The unbalanced equation is: $\ce{Fe + Cl2 -> FeCl3}$

Step2: Balance the chlorine atoms

There are 2 Cl atoms on the left and 3 on the right. The least common multiple of 2 and 3 is 6. So, put a coefficient of 3 in front of $\ce{Cl2}$ and 2 in front of $\ce{FeCl3}$: $\ce{Fe + 3Cl2 -> 2FeCl3}$

Step3: Balance the iron atoms

Now there are 2 Fe atoms on the right, so put a coefficient of 2 in front of Fe on the left: $\ce{2Fe + 3Cl2 -> 2FeCl3}$

Step1: Write the unbalanced equation

Aluminum carbonate ($\ce{Al2(CO3)3}$) decomposes to form aluminum oxide ($\ce{Al2O3}$) and carbon dioxide ($\ce{CO2}$). The unbalanced equation is: $\ce{Al2(CO3)3 -> Al2O3 + CO2}$

Step2: Balance the carbon and oxygen atoms (from carbonate)

There are 3 $\ce{CO3^{2-}}$ groups in $\ce{Al2(CO3)3}$, so we need 3 $\ce{CO2}$ molecules. Put a coefficient of 3 in front of $\ce{CO2}$: $\ce{Al2(CO3)3 -> Al2O3 + 3CO2}$

Step1: Write the unbalanced equation

Magnesium (Mg) reacts with silver nitrate ($\ce{AgNO3}$) to form silver (Ag) and magnesium nitrate ($\ce{Mg(NO3)2}$). The unbalanced equation is: $\ce{Mg + AgNO3 -> Ag + Mg(NO3)2}$

Step2: Balance the nitrate ions

There are 2 nitrate ions on the right, so put a coefficient of 2 in front of $\ce{AgNO3}$: $\ce{Mg + 2AgNO3 -> Ag + Mg(NO3)2}$

Step3: Balance the silver atoms

Now there are 2 Ag atoms on the left, so put a coefficient of 2 in front of Ag on the right: $\ce{Mg + 2AgNO3 -> 2Ag + Mg(NO3)2}$

Answer:

$\boldsymbol{\ce{2Fe + 3Cl2 -> 2FeCl3}}$

Part b